Now that Nissan Motor Corp. is ramping up production of U.S. made Leaf electric cars and battery packs, the Japanese auto maker is gearing up new efforts to get sales out of the slow lane.

With help from a $1.4 billion federal loan, Nissan since last October has had a highly automated factory at its sprawling manufacturing complex in Smyrna, Tenn. churning out 600-pound lithium-ion battery packs that fit into the bodies of Leafs assembled at the nearby vehicle assembly plant. The Smyrna battery plant is the largest lithium-ion auto battery factory in North America, company officials said.

Nissan opened the battery plant to journalists this week, showing off automated battery cell assembly lines and workers clad in head-to-toe white jumpsuits handling battery components in low-humidity clean rooms. Lithium-ion batteries are tricky to build, and must age for several weeks before they can be charged and installed in a car.

The only problem apparent to a visitor is that the plant is operating at a crawl. Nissan has the equipment installed to build about 200,000 battery packs a year — but plant managers say so far facility’s 300 workers are only building enough to keep pace with U.S. Leaf demand, which currently is running at about 2,000 vehicles a month.

To jump start sales, Nissan dropped the starting price of the Leaf to $28,800 — down $6,400 from the 2012 model. Company executives say that price cut was made possible in large measure by the savings on shipping and costs related to foreign exchange made possible by moving production of Leafs for the U.S. market to Tennessee.